Massachusetts State Police detectives are seen at the Danvers High School Wednesday, Oct. 23, 2013, in Danvers, Mass. / Mark Garfinkel/Boston Herald AP

by John Bacon and Gary Strauss, USA TODAY

by John Bacon and Gary Strauss, USA TODAY

Authorities in the quiet Massachusetts town of Danvers are trying to determine why a beloved young math teacher was murdered Tuesday in the bathroom of her high school.

A judge on Wednesday ordered Philip Chism, 14, held without bail on a murder charge at an arraignment hearing in adult court, just hours after the body of Colleen Ritzer, 24, was found in woods near Danvers High School 20 miles north of Boston.

Ritzer's death came just a day after a 12-year-old armed with his parents' handgun killed Sparks, Nev., middle school math teacher Mike Landsberry and wounded two students before shooting himself.

Essex District Attorney Jonathan Blodgett said a search began for Ritzer Tuesday after police were notified that she had not returned to her Andover home from work and was not answering her cellphone.

Investigators found blood in a school bathroom and soon located her body. Blodgett said the teen, who transferred to Danvers High this year, stabbed Ritzer, then dumped her body in the woods behind the campus. Investigators said in court documents that Chism's arrest was made based on his statements and corroborating evidence at multiple scenes. They said they also recovered video surveillance.

"This is a terrible tragedy for Colleen Ritzer and for the entire Danvers community," Blodgett said.

Chism is due back in court Nov. 22 for a probable cause hearing. The youth, a leading scorer on Danvers' junior varsity soccer team, had been reported missing Tuesday after failing to return home from school, Blodgett said. He was found about 12:30 a.m. Wednesday.

Kyle Cahill, a junior, said he knows Chism from the soccer team. He said the 14-year-old moved to Massachusetts from Tennessee before the school year. "He wasn't violent at all. He was really the opposite of aggressive," said Cahill, who called Chism a nice, quiet kid.

Blodgett said Ritzer was "a very respected, loved teacher." She often used Twitter to stay in touch with her students, last tweeting geometry homework links two days ago.

Ritzer graduated from Andover High School in 2007 and earned a math degree in 2011 from Assumption College in Worcester. She had taught for two years, and still lived at the family home with her younger brother and sister.

Chris Weimert, 17, was a student in Ritzer's geometry class last year. She was a warm, welcoming person who would stand outside her classroom and say hello to students she didn't teach, Weimert said.

"She was the nicest teacher anyone could ever have. She always had a warm smile on her face," he said.

She often tweeted encouragement to her students, such as "Good luck to sophs/juniors on PSATs tomorrow :) I hope there's a proof on there...that would be so much more fun!"

She had a few hundred Twitter followers, with whom she also shared personal shreds of her life - usually punctuated with exclamation points. "Attempting to make my first apple crisp!" was a recent one; "Lots of Full House episodes on Nick tonight!!" was another.

A more serious tweet in a time of tragedy: "This world is a crazy place. Love who you love and live every day. Thoughts and prayers to those affected at the Boston Marathon."

Mary Duffy, who lives next door to the Ritzer family, told the Boston Herald she knew Colleen for almost her entire life.

"If every family had a daughter like Colleen Ritzer, it would be a wonderful world," Duffy said. "She always wanted to teach math.

"She was a quiet, pleasant girl with many friends. She was just like the ideal daughter. She is. This family is a family of America. They are the ideal family, they are friendly, they are loving, close."

Danvers police were at the school most of the night. Town officials called parents about 4:45 a.m. Wednesday, saying only that there was a police presence at the school. Classes at all seven schools in the Boston suburb were canceled, boston.com reported.

Mark Nolan, who coached Chism in a Clarksville, TN., youth soccer league, said the teen caused no problems on the field or during practice. Nolan said he was "absolutely shocked" to hear Chism had been implicated in a murder.

"I find it hard to believe. He isn't anybody I would have thought would be involved in something like that," said Nolan.